By means of the Dirac procedure, we re-examine Yangs quantized space-time model, its relation to Snyders model, the dS special relativity and their UV-IR duality. Starting from a dimensionless dS5-space in a (5+1)-dimensional Mink-space a complete Yang model at both classical and quantum level can be presented and there really exists Snyders model, the dS special relativity and the duality.